I don't think we can directly reduce self-vote/curation returns of autovoters at the blockchain level, it would become kind of messy. I prefer the other route by increasing the rewards of active authors and active curators and I'd be open for additional tools and methods to help with that. I think most of those rewards would have to come from the author reward pool or DHF since curation is hard to adjust aside from downvoting where one would deem votes to be mainly auto and author undeserving as well.